Engineering a gluconate bypass carbon entry architecture for robust stationary phase biomanufacturing

Area of Science:

• Metabolic Engineering
• Synthetic Biology
• Biotechnology

Background:

• Two-stage bioprocesses decouple cell growth from product synthesis for efficient biomanufacturing.
• High production in stationary phase cultures often leads to metabolic decline.
• Pyruvate accumulation in E. coli inhibits stationary-phase glucose uptake.

Purpose of the Study:

• To engineer a metabolic architecture that sustains stationary phase productivity.
• To decouple glucose uptake from pyruvate-mediated inhibition.
• To enhance NADPH cofactor regeneration for biosynthesis.

Main Methods:

• Designed and implemented a gluconate-bypass (GBP) metabolic architecture in E. coli.
• Rerouted carbon flux around glucose-6-phosphate.
• Validated the GBP architecture using NADPH-dependent L-alanine production.

Main Results:

• The GBP architecture enabled prolonged stationary phase productivity by decoupling glucose uptake from pyruvate inhibition.
• Glucose oxidation via GBP intrinsically co-generated NADPH for biosynthetic pathways.
• Achieved a record L-alanine titer of 197 g/L with a 1.6-fold increase in production longevity.
• Resulted in an improved production yield of 94%.

Conclusions:

• The GBP metabolism supports robust stationary phase biosynthesis.
• This metabolic framework is versatile for efficient production of pyruvate-derived chemicals.
• GBP offers a solution to metabolic decline in high-flux bioproduction systems.